title: The role of CT pulmonary angiography in the investigation of unilateral pleural effusions.
abstract: BACKGROUND
  Pulmonary embolism (PE) is frequently cited as a common primary cause of unilateral pleural effusion, but in clinical practice appears to be uncommon.
  
  
  OBJECTIVE
  In order to evaluate this observation, CT pulmonary angiography (CTPA) was performed in consecutive patients presenting to a single centre with a new uninvestigated unilateral pleural effusion and no clear cause and was supplemented by delayed-phase thoracic CT, optimized for visualization of the pleura.
  
  
  METHODS
  All patients underwent standard clinical assessment and pleural investigations in line with recent national guidelines and were followed up for a minimum of 1 year or until histological/microbiological diagnosis.
  
  
  RESULTS
  One hundred and fifty patients were recruited, and of these, 141 had a CTPA. PEs were detected in 9/141 (6.4%) patients, and of these, 8/9 were subsequently diagnosed with pleural malignancy. In only 1 case was PE clinically suspected and in no case was PE the primary cause of effusion; 9.8% (8/82) of patients who were ultimately diagnosed with pleural malignancy had PE at presentation.
  
  
  CONCLUSIONS
  This study indicates that PE is a frequent concomitant finding in patients with malignant effusions but uncommon as a primary cause of unilateral effusion. In addition, it highlights the known difficulty of clinical diagnosis of PE in the context of malignancy. In view of this, we recommend that CTPA combined with pleural-phase thoracic CT should be considered at presentation when investigating patients with suspected malignant pleural effusion.
authors.affiliation: Academic Respiratory Unit, University of Bristol and North Bristol Lung Centre, Bristol, UK.
authors.forename: Clare
authors.initials: C
authors.lastname: Hooper
authors.forename: Isabel
authors.initials: I
authors.lastname: Laurence
authors.forename: John
authors.initials: J
authors.lastname: Harvey
authors.forename: Anna
authors.initials: A
authors.lastname: Morley
authors.forename: Mike
authors.initials: M
authors.lastname: Darby
authors.forename: Anthony
authors.initials: A
authors.lastname: Edey
authors.forename: Nick
authors.initials: N
authors.lastname: Maskell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods; D002289:Carcinoma, Non-Small-Cell Lung / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000000981:diagnostic imaging* / Q000209:etiology; D016066:Pleural Effusion, Malignant / Q000000981:diagnostic imaging* / Q000209:etiology; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000150:complications / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed